Improvement in rotary valves and variable cut-offs



R. T. P. ALLEN.

Rotary Valves and Variable Cut-Offs.

No. 137,163, Patented March25,l 873.

Witness: v V nve t r.

Attorneys.

AM, PHOT0-LITH06RAFHIO 00, :v. Mossy/ms mocmsj.)

the left.

"rron.

ROBERT T. I. ALLEN, OF FAR-MDALE, KENTUCKY.

IMPROVEMENT IN ROTARY VALVES AND VARIABLE CUT-QFFS.

Specification forming part of Letters Patent No. 13?,163, dated March 25, 1873.

To all whom it may concern:

Be it known that I, It. T. P. ALLEN, of Farmdale, in the county of Franklin and in the State of Kentucky, have invented certain new and useful Improvements in Rotary Valve and Cut- Ol f; and do hereby declare that the followin gis a full, clear, and exact description thereof,referencc.being had to the accompanying drawing and to the letters of reference marked thereon making a part of this specification.

The nature of my invention consists in the construction and arrangement of a rotary valve and variable cutoff for steam-engines, as will be hereinafter more fully set forth.

In order to enable others skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which-- Figure 1 is a longitudinal section of the entire valve in position. Fig. 2 is a view of the "alve-seat. Fig. 3 is a plan view of the variable cut-oh, and Fig. 4 is a bottom view of the valve.

A represents the Valveseat, provided with central circular exhaust-port a and two steamports, I) b, one on the right and the other on B is a disk forming the variable cutoff, placed on the valve-seat A and provided with similar exhaust and steam ports a and b I). 0 represents the valve which is hollow, rests upon the cut'oflf, and provided with a diaphragm, D, leaving a steamport, b and in the under side of the diaphragm is formed the exhaust a The variable cutoff B is not intended to move except as actuated by the governor. The various steam-ports are made one-eighth of the circle, because oneeighth passing over one-eighth gives one-fourth revolution or onehalf cut-oft at half stroke. For a cut-off at one-third stroke, the ports should be onetwelfth of the circle. The entrance-port of the rotating valve 0 is one-eighth, while the exhaust-port is three-eighths, because threeeighths passing over one-eighth makes onesteam is removed and the valve will have to be held down on its seat, which can easily be provided for by various means.

Tlus device furnishes a perfectly-balanced valve, and, in fact, converts the valve into a steam'chest and dispenses with the inclosing steam-chest. It also enables the engineer to see at every movement if there is any leak in the valve.

I have not deemed it necessary to show the means for introducing the steam into the valve, as this forms no part of my present application; but I propose to make the stem G, by which the valve is rotated, hollow and large enough for the passage of the steam, and to pass this stem through an enlargement of the steam-pipe, with tight joints, and to rotate the valve by a crank above the crossing of the two pipes and connected with the ordinary rockshaft; or, the valve may be rotated by ordinary gearing of cog-wheels connected with a cog-wheel on the main shaft. The governor is to be connected with the variable cut-oft disk B by means of an octant sector, (I, gearing into cogs c on the periphery of the disk, the sector being moved by shaft and crank.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

The hollow valve 0, forming a steam-chest, in combination with the cut-off B provided with teeth 0, the cogged sector d, and valve-seat A, all provided with the inlet and exhaust ports, as described, and operated substantiallyin the manner and for the purposes herein set forth.

In testimony that I claim the foregoing I have hereunto set my hand this 28th day of December, 1873.

ROBT. T. P. ALLEN. Vv'itnesses:

A. W. OVERTON, JNo. 0. Jonas. 

